This is a note to let you know that I've just added the patch titled
usb: cdns3: remove fetched trb from cache before dequeuing
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-cdns3-remove-fetched-trb-from-cache-before-dequeuing.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1301c7b9f7efad2f11ef924e317c18ebd714fc9a Mon Sep 17 00:00:00 2001
From: Pawel Laszczak <pawell@xxxxxxxxxxx>
Date: Tue, 15 Nov 2022 05:00:39 -0500
Subject: usb: cdns3: remove fetched trb from cache before dequeuing
From: Pawel Laszczak <pawell@xxxxxxxxxxx>
commit 1301c7b9f7efad2f11ef924e317c18ebd714fc9a upstream.
After doorbell DMA fetches the TRB. If during dequeuing request
driver changes NORMAL TRB to LINK TRB but doesn't delete it from
controller cache then controller will handle cached TRB and packet
can be lost.
The example scenario for this issue looks like:
1. queue request - set doorbell
2. dequeue request
3. send OUT data packet from host
4. Device will accept this packet which is unexpected
5. queue new request - set doorbell
6. Device lost the expected packet.
By setting DFLUSH controller clears DRDY bit and stop DMA transfer.
Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Pawel Laszczak <pawell@xxxxxxxxxxx>
Acked-by: Peter Chen <peter.chen@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221115100039.441295-1-pawell@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/cdns3/cdns3-gadget.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
--- a/drivers/usb/cdns3/cdns3-gadget.c
+++ b/drivers/usb/cdns3/cdns3-gadget.c
@@ -2614,6 +2614,7 @@ int cdns3_gadget_ep_dequeue(struct usb_e
u8 req_on_hw_ring = 0;
unsigned long flags;
int ret = 0;
+ int val;
if (!ep || !request || !ep->desc)
return -EINVAL;
@@ -2649,6 +2650,13 @@ found:
/* Update ring only if removed request is on pending_req_list list */
if (req_on_hw_ring && link_trb) {
+ /* Stop DMA */
+ writel(EP_CMD_DFLUSH, &priv_dev->regs->ep_cmd);
+
+ /* wait for DFLUSH cleared */
+ readl_poll_timeout_atomic(&priv_dev->regs->ep_cmd, val,
+ !(val & EP_CMD_DFLUSH), 1, 1000);
+
link_trb->buffer = cpu_to_le32(TRB_BUFFER(priv_ep->trb_pool_dma +
((priv_req->end_trb + 1) * TRB_SIZE)));
link_trb->control = cpu_to_le32((le32_to_cpu(link_trb->control) & TRB_CYCLE) |
@@ -2660,6 +2668,10 @@ found:
cdns3_gadget_giveback(priv_ep, priv_req, -ECONNRESET);
+ req = cdns3_next_request(&priv_ep->pending_req_list);
+ if (req)
+ cdns3_rearm_transfer(priv_ep, 1);
+
not_found:
spin_unlock_irqrestore(&priv_dev->lock, flags);
return ret;
Patches currently in stable-queue which might be from pawell@xxxxxxxxxxx are
queue-6.1/usb-cdns3-remove-fetched-trb-from-cache-before-dequeuing.patch
